Invalid signature detected" message prompt on every boot up. How do I fix? - CPUs, Motherboards, and Memory - Linus Tech Tips
Windows 7: "Secure Boot Violation" after April Patch day – Born's Tech and Windows World
Secure Boot Violation” may display when Secure Boot is enabled in BIOS and attempting to boot into Ubuntu and Debian - ThinkStation - Lenovo Support US
Notebook] When starting up the laptop, a 'Secure Boot Violation' message appears | Official Support | ASUS Global